1. Field of the Invention
The present invention relates to a display device which uses a flat display panel, such as an electro-luminescent (EL) display panel.
2. Description of the Related Art
Research and development of flat display panels is flourishing in recent years. Flat display panels include liquid crystal display panels using transmission light, plasma display panels using discharge phenomena, field emission display panels, and EL display panels using electroluminescence. All display panels which display an image by using a dot matrix have a plurality of pixels arranged in a matrix.
To increase the visibility of a flat display panel, its surface is sometimes optically processed. For example, to suppress reflection of external light on the display surface of a flat display panel, an AR (Anti-Reflection) coating is applied to the display surface. Jpn. Pat. Appln. KOKAI Publication No. 2000-322000 discloses a technique for forming a microlens array on the display surface of a flat display panel to increase its light emission ratio. Alternatively, to increase both the surface directivity and the luminance of a flat display panel, a prism sheet having a number of prisms with triangular sections is bonded to the display surface of the flat display panel.
When an optical means such as a microlens array or a prism sheet is arranged on the display surface of a flat display panel, the emission ratio of light toward the front side increases. On the other hand, if, e.g., a red pixel (R) radially emits light, and a light component that has reached the upper portion of an adjacent green pixel (G) is refracted or reflected by the optical means opposing the green pixel (G) and emerges to the front side, the light that emerges from the red pixel (R) diverges to the green pixel (G) which actually emits green light. For this reason, the area where only the color of the green pixel (G) can be seen becomes small.